Within the rich and varied medley of Texas wildlife, few creatures are as fascinating and beneficial as the Lone Star State's 32 species of bats. No other group of Texas mammals is more important to the balance of nature, and none is more diverse. Red, silver-haired, and spotted bats are strikingly colorful. Ghost-faced bats look as exotic as any dinosaur. Mexican free-tailed bats sing like warblers. Greater bonneted bats have narrow wings for jet-like flight, while big-eared bats fly like helicopters on broad wings. Most Texas bats eat insects, often those that farmers find most damaging, and bats have enormous appetites: A single Texas colony of freetailed bats consumes billions of insects every summer night. Other bat species are essential pollinators of desert plants.
Yet bats, active only at night, are seldom seen, often misunderstood, and usually feared. Many people still believe bats are blind, flying mice that carry diseases and become tangled in women's hair. In truth, bats are more closely related to people than to mice, they generally have excellent eyesight, and they are far too clever to entangle themselves in anyone's hair. Bats seldom transmit disease to people or pets; when left alone, they are among our safest neighbors. Their fearsome reputation is completely undeserved.
Worldwide, there are more than 1,100 kinds of bats--nearly a fourth of all mammal species. Bats are found everywhere except in the most extreme desert and polar regions, although most live in tropical forests, where they feed on fruit, nectar, pollen, and insects. A few tropical species feed on small fish, frogs, mice, and birds.
Despite their notoriety, vampire bats, which do indeed feed on blood, account for only three of the world's species and live only in Latin America. Texas bats feed exclusively on insects, except for pallid bats that also prey on scorpions and centipedes, and long-nosed and long-tongued bats that eat nectar and pollen.
Etymology
Latin: Tadarida (withered toad)
Latin: brasiliensis (belonging to Brazil)
Appearance
Mexican free-tailed bats have long, narrow wings; their tails extend beyond the tail membrane for about a third of its length. Fur is gray in new molt, then fades to rusty brown. They have large, rounded ears and vertical wrinkles on their upper lips. Forearm: 1.5 to 1.8 inches (38 to 46 mm). Wingspan: 11.3 to 13.4 inches (287 to 340 mm).
Mating and Rearing Young
Mating occurs in March and April. After a gestation period of approximately 11 weeks, each mother bears a single pup, usually in June.
Habitat and Food
These bats occupy a broad range of habitats, from deserts to pine/oak forests and piñon/juniper woodlands, and rank among Texas' most ecologically and economically important animals. An estimated 100 million live in the Hill Country alone, where each million bats consume about 10 tons of insects nightly. They feed on a variety of prey, including moths, beetles, flying ants, leafhoppers, midges, mosquitoes, water boatmen, and green lacewings. Each night from spring to early summer, they catch billions of migrating moth pests, especially corn earworm, army and tobacco budworm moths, sparing farmers millions of dollars in crop losses.
Roosting Behavior
Most Mexican free-tailed bats roost in caves, but many live in abandoned mines and in tunnels, buildings, bridges, bat houses, and cliff-face crevices. Nursery colonies can contain hundreds to millions of bats. (Bracken Cave, near San Antonio, hosts about 20 million Mexican free-tailedbats--the largest aggregation of warm-blooded animals on Earth.) Most of these bats migrate to Mexico for the winter and begin returning to Texas nursery sites in early March. Thousands of these bats remain in Texas year-round, entering torpor during winter extremes, but emerging to feed on warm evenings.
Human Encounters
Mexican free-tailed bats are the most commonly encountered bats in Texas, and their spectacular evening emergences are easily observed (see page 66). They are often seen around street lamps, and they readily occupy bat houses.
